I use git and love it. However, I haven't really heard anything bad about Mercurial (they say on Windows it is better, but I haven't have any problems with git either). Historically git might have been a bit hard to learn, but those times are long gone. Git gives quite verbose output from its commands, including hints about what you might want to do next, whereas Mercurial uses e.g. svn-style status info, which is very compact. The basic commands work almost identically in both git and Mercurial. In any case, distributed version control system is the way to go (third option in that category would be Bazaar (bzr), but it is not as widely used and much slower than git and hg).
One thing fundamentally different with svn and git is that svn branches are just copies of the directory (and tags are read-only copies), whereas git (and I believe Mercurial also) repository is a "pool" of commits and branches + tags are just pointers to certain commits. This leads to smaller repo size and super-fast, very cheap branching.
Here's some things why I use VC for lone projects also:
* Branching - I can do something experimental in a separate branch (e.g. test SFML instead of SDL) and also continue work on the "stable" and then if I decide experimental stuff is good, merging them together is easy.
* Sense of going forward - commits show that I've managed to to something.
* Generate changelogs.
* Find out where a bug was introduced by using half-automated (could actually be fully) git-bisect binary search on the commits.